he goal of this project is to define immune mechanisms and iral characteristics important in the pathogenesis of Aleutian isease (AD). Monoclonal antibodies were used to study ntigenic differences among strains of ADV. Antibodies with eactivity for tissue derived Utah I ADV or tissue culture erived ADV-G were clearly delineated. Other strains could be dentified by using a large panel of mAbs. New information was btained regarding the specific antigenic determinants ecognized by several mAbs whose precise reactivities were bscure earlier. Thus, some antibodies recognize the major iral structural proteins of ADV-G while others recognize the ajor viral structural proteins of tissue derived Utah I virus. till others react with tissue associated low molecular weight roteins probably resulting from in vivo proteolysis of larger recursors. Although some of the mAbs had these restricted eactivities, most had broader reactivity for antigen common to ome or all of the strains. Selected mAbs were used to study he expression of particular ADV-G virus associated antigens uring infection of CRFK cells. Some mAbs recognize redominantly antigens expressed in the cytoplasm of infected ells while others recognize antigens in the nucleus. These Abs may provide probes allowing us to better understand the inetics of in vitro infection and restrictions some cells are ble to exert on viral replication. We also demonstrated viral ntigens in the tissues of infected mink using mAbs. Distinct train specific patterns of fluorescence were observed. If articular viral antigens are especially prone to be involved n immune complex formation and deposition, we hope to identify hem in vivo using the mAbs that are now available. Such nformation should clarify our understanding of AD pathogenesis.